Affiliation: | 1. Department of Medicine and Oral Surgery, Dental Sciences Group – Health Sciences Research Centre, Instituto Superior de Ciências da Saúde Norte, , Paredes, Portugal;2. Department of Epidemiology, Portuguese Institute of Oncology (IPO Porto), , Porto, Portugal;3. Oral Medicine, Department of Clinical & Diagnostic Sciences, King's College London Dental Institute, WHO, Collaborating Centre for Oral Cancer, , London, UK |